To this day, six of the seven states deny they were breached, based on their own cyber investigations

Receive the latest national-international updates in your inbox

FILE - Voters casts their ballots in the presidential primary at ChiArts High School on March 15, 2016, in Chicago, Illinois.

The U.S. intelligence community developed substantial evidence that state websites or voter registration systems in seven states were compromised by Russian-backed covert operatives prior to the 2016 election — but never told the states involved, according to multiple U.S. officials.

Top-secret intelligence requested by President Barack Obama in his last weeks in office identified seven states where analysts — synthesizing months of work — had reason to believe Russian operatives had compromised state websites or databases.

Three senior intelligence officials told NBC News that the intelligence community believed the states as of January 2017 were Alaska, Arizona, California, Florida, Illinois, Texas and Wisconsin.

The officials say systems in the seven states were compromised in a variety of ways, with some breaches more serious than others, from entry into state websites to penetration of actual voter registration databases.

NBC News reached out to all seven states that were compromised, as well as 14 additional states the Department of Homeland Security says were probed during the 2016 election.

To this day, six of the seven states deny they were breached, based on their own cyber investigations.